This invention relates to an exposure control system for cameras capable of making intentional double and multiple exposures on the same frame of film.
Many roll film cameras using spring-powered shutter mechanism also utilizes a device for energizing the shutter-operating spring when the film is advanced one frame after the frame exposure has been completed. Specifically, they employ so called self-cocking device.
In a camera having a self-cocking device, however, the shutter mechanism and film transporting mechanism are interlinked to each other. Hence, in order to impart to the camera the capability of superimposing a second exposure on the once exposed frame of film, that is, to produce a very complicated mechanism must be provided.
Generally, when the film winding lever is turned, the film is advanced one frame and the shutter mechanism is charged or coded. To superimpose a number of shots, it has been the common practice in the prior art to provide a special control mechanism that, upon actuation, permits the film to remain stationary and the film counter to stand still despite the operation of the film winding level. In addition to the necessity of furnishing a complicated control mechanism, this arrangement has the disadvantage that the necessary number of parts are increased and the cost of production of the camera is raised.
Moreover, with an automatic exposure control camera, when two or more shots superimposed while the automatic exposure mode is set, each shot admits a full exposure adjusted independently of the others, to the same frame of film. Hence, the larger the total number of shots superimposed, the more the frame will be overexposed.